Hair Foundation
Healthy Hair: How to Keep It Healthy and Looking Good

February 20, 2008
James L. Breeling

Things That Can Hurt Your Hair and Its Appearance

  • Excessive Sun Exposure
  • Sun and Salt Water
  • Chlorine in the Swimming Pool
  • Excessive Heat in Hair Styling and Blow Drying
  • Chemicals in Hair Care Products

    Choosing Hair Care Products That Are Right for You

  • Shampoos
  • Conditioners
  • Hair Styling Agents
  • Permanent Waving
  • Straighteners
  • Coloring Agents

    People with healthy, undamaged hair often don't realize how fortunate they are. The daily routine of brushing teeth, washing face and combing/brushing hair is hardly given a second thought.

    However, many people are not so fortunate in the health and appearance of their hair. Instead of healthy and luminous, it may be discolored, tangly, hard to manage and be plagued with physical damage such as broken hair shafts and split ends.

    How does a person with healthy hair keep it healthy and looking good? How does one avoid the pitfalls that result in damaging the health and appearance of hair? Since it is best to keep hair healthy in the first place, let's look at pitfalls first, and then at advice regarding how to choose hair care products.

    Things That Can Hurt Your Hair and Its Appearance

    Hair can be damaged by physical injury, chemical injury, thermal (heat) injury, and by disease. When we eliminate disease from the list, we are left with types of damage that are more or less under our control. We can prevent much of the damage that can be done to our hair.

    Hair is a biologic fiber (see How and Why Hair Grows). The hair fiber is constructed largely from the proteins called keratins, which provide both the central core of the hair shaft and the cuticle scales that armor the shaft and give it pliable strength. When we talk about physical, chemical or thermal damage to hair, we are talking about damage to the keratins. Damage usually affects the cuticle scales first; this reduces the pliable strength of the hair and makes it harder to manage, and it opens the way for damage to the keratins that make up the hair shaft's central core.

    Excessive Sun Exposure

    We are familiar with advice to avoid excessive sun exposure that can damage our skin. The same advice holds for avoiding excessive sun exposure that can damage hair. As with sun damage to skin, it is the ultraviolet component of solar radiation that damages hair. The ultraviolet wavelengths break chemical bonds in the keratin proteins that constitute most of the bulk and strength of the hair shaft. Weakened keratin proteins weaken the hair shafts and renders then more likely to become dry and "weathered" in appearance. It also makes them weaker and more likely to break when combed or brushed.

    Wearing a hat is the easiest way to avoid sun damage to hair. Ultraviolet protection is claimed for some hair care products including shampoos, conditioners and sprays.

    Sun and Salt Water

    Sea water is not only salty, it is alkaline, in contrast to hair keratins which are slightly acidic. Bathing hair keratins in the alkaline solution of sea water can damage the keratins. The combination of sea water and solar radiation also has bleaching effects. Various recipes have been offered for products that are claimed to protect against the combination of salt water and sunlight-for example, before entering the water, give the hair a protective coating of a grease such as cocoa butter that prevents sea water contact with hair. A readily available method for limiting hair damage is to shampoo and thoroughly rinse hair in fresh water after leaving the ocean, then applying a protein conditioner.

    Chlorine in the Swimming Pool

    Chlorine is a potent bleaching agent and causes severe damage to hair keratins. Thus, chlorine in the swimming pool can both lighten and weaken hair. Damage to keratins can be even more severe when the proteins have already been damaged by chemical or thermal hair styling treatment. Chorine-damaged hair can manifest its damage in hair breakage, split ends, decoloration and difficulty in styling. The belief that swimming pool chlorine causes blond or gray hair to turn green is not altogether true; the greenish sheen comes from metals such as copper or iron that are dissolved in pool water and are oxidized by chlorine after they are taken up by hair shafts.

    A first line of defense against swimming pool chlorine is (1) to rinse hair thoroughly in fresh water immediately upon leaving the pool, and (2) shampoo with a product that will limit chlorine damage to keratins. A shampoo of this type should be acid/alkaline (pH) neutral (see Hair Styling Product Ingredients) and contain sodium thiosulfate which neutralizes chlorine. Some hair experts recommend limiting or preventing chlorine damage by applying a protective conditioner covered by a latex or silicon cap before entering the pool.

    Excessive Heat in Hair Styling and Blow Drying

    Keratin proteins are easily damaged by excessive heat. Two common ways for this thermal (heat) damage to occur is by (1) use of heated implements for hair straightening or styling, and (2) using the blow dryer at too high a temperature for too long when drying hair.

    Hair styling implements should be used at the lowest effective temperature for the least amount of time that will produce a desired effect. They should be used only as often as necessary to maintain a styling effect; too frequent application of heated styling implements can cause an accumulation of hair damage over time.

    The blow dryer should never be used at high heat to dry hair. Blow drying should be done on the "cool" setting to prevent thermal damage to hair keratins.

    Excessive Brushing

    Myths die hard, and one of the most tenacious is the belief that women (and men) should brush their hair with at least 100 strokes daily. The belief may have been credible-and useful-in days when bathing and hair-washing was less frequent because running water was not readily available. Hair brushing in those circumstances was an effective way to remove dead skin cells and distribute hair oils. Today the belief may do more harm than good. It is known today that too-frequent and too-hard brushing can physically damage the cuticle of hair shafts and result in hair weakening and hair breakage. While "100 strokes a day" was once useful to clean and lubricate the hair, these functions are performed more effectively today by appropriate use of shampoos and conditioners.

    It is still necessary to comb and brush hair, however, but damage can be limited or prevented by observing some rules:

  • Never back-brush or back-comb hair; this pulls hair in the wrong direction and can be damaging.

  • Don't brush wet or damp hair; dry it first.

  • Use a wide-toothed comb instead of a brush, except when a brush is absolutely necessary. Use a comb rather than a brush to work through hair tangles, and do it slowly and with care rather than "ripping" through the tangle.

  • Hair Care Products

    Hair damage caused by overly harsh shampoos, styling agents and hair straighteners is most commonly caused by the alkalinity of the agents. On the pH (alkaline/acidic) scale, hair is somewhat acidic with a pH of 4.4 to 5.5. The pH scale has values from 0 to 14; pH of 7 is neutral, from 7 to 14 denotes increasing alkalinity, from 7 to 0 denotes increasing acidity. When slightly acidic hair is bathed in an alkaline solution, the cuticle scales swell and lift away from the cortex core. The immediate effect is to give the hair a rough texture, rather dull in appearance. The lifting of cuticle armor away from the cortex also opens the cortex to chemical attack. This is a useful property when the purpose is to change hair color; when cuticle armor lifts away from cortex, a hair coloring agent is able to penetrate the cortex and stain cortex keratins with the desired color. When this is done too frequently, however, there can be a accumulation of damage to the cortex.

    The effect of an alkaline solution is immediately counter-acted when the hair is bathed in a moderately weak acidic solution such as vinegar (a solution of acetic acid). The vinegar (or lemon juice) rinse was a normal procedure in past years when soap-which is slightly alkaline-was the only cleansing agent available for shampooing hair. The acidic bath heals the swollen cuticle and restores the smooth texture and sheen of hair.

    Some alkaline styling agents are left in the hair for extended periods of time. This can cause cumulative hair damage.

    Choosing Hair Products That Are Right for You

    What criteria can be used to make a rational choice of hair-care products? Objective criteria are the chemical ingredients of a product-information one gets from the product label.

    Subjective criteria are the consumer's response to the product-ease of use, how well it does the job for which it was chosen, whether it provokes any allergic or irritating responses, and esthetic considerations.

    Objective and subjective criteria can be mutually useful-for example, the presence of a chemical ingredient listed on the product label seems to be associated with an irritating reaction on scalp skin.


    The purpose of a shampoo is to remove dirt, dead skin and excess oil from the scalp and hair, and leave the hair attractively pliant and glossy. Most shampoos today contain a detergent as the cleansing agent. Other ingredients commonly include chemicals added for specialty purposes a consumer may find attractive:

  • Conditioners and softeners to make the hair pliant and glossy after the shampoo;

  • Fragrances to leave the hair with an attractive aromatic quality;

  • Sequestering agents to remove minerals from "hard" water that may make cleansing more difficult; and,

  • Foaming agents which contribute little to a shampoo's cleansing power, but address the belief of consumers that "foam" or "lather" is necessary for effective cleansing.

  • A growing market for "organic" products is represented in shampoos that (1) use soap rather than detergent as the cleansing agent, and (2) add "herbal extracts" and vitamins to the list of ingredients.

    A number of anti-dandruff shampoos are available (see Dandruff). Anti-dandruff ingredients are zinc pyrithione (also called zinc omadine) and selenium sulfide. Which anti-dandruff shampoo will work best for any individual is difficult to predict; the consumer must usually decide on the basis of results. Excessively oily, scaly or itchy dandruff that persists may need medical attention.

    In choosing a shampoo based on objective criteria, remember that hair is slightly acidic (see Hair Styling Product Ingredients). Most shampoos are acidic to greater or lesser degree (pH of 5 is slightly acidic, pH of 3 is more acidic). The shampoo of greater acidity (lower pH) tends to have greater cleansing power-an attribute not needed by most people whose hair is not especially dirty or oily.

    Another set of objective criteria is to identify the ingredient listed as a detergent. Detergents can be categorized into three chemical groups:

  • Anionic-heavier duty cleansers that may need more post-shampoo conditioning. Detergents in this group include sodium lauryl sulfate, sodium laureth sulfate, TEA lauryl sulfate, ammonium laureth sulfate, ammonium laureth sulfite, DEA lauryl sulfate and sodium olefin sulfonate.

  • Nonanionic-milder cleansing agents that leave the hair softer and glossier. Detergents in this group include polysorbates, nonoxynols and polyoxymers.

  • Amphoterics-milder cleansing agents, non-irritating to eyes, leave the hair soft and glossy. Detergents in this group include cocoamphotericglycinate, cocoamphopropionate and cocoamphocarboxyprionate. The amphoteric shampoos are sometimes called "baby shampoos". Persons with kinky hair generally should use shampoos that are mildly cleansing, with a pH of about 5. This type of shampoo is generally more effective in cleansing and "detangling" hair.

  • Conditioners

    The purpose of a conditioner is to make hair easy to comb, easy to style and have an attractive gloss after shampooing. Some shampoos have an added conditioner, or a conditioner may be applied separately following the shampoo. Conditioners can be categorized in several ways:

  • Cationic detergents-most commonly quaternary ammonium compounds, they are ingredients in both shampoos and hair conditioners. They effectively restore roughened cuticle and decrease static electricity in newly shampooed hair. Cationic detergents are a good choice in shampoo and conditioner for persons with dyed or permanent-waved hair.

  • Film forming conditioning agents-also called "hair thickeners", they are polymer agents such as polyvinylpyrrolidone (PUP). The polymer fills defects in the hair shaft, enhances hair gloss and reduces static electricity. The polymer coating thickens the hair shaft; for this reason, film-forming conditioners are not appropriate for fine hair because the added thickness and weight makes the hair difficult to style.

  • Protein conditioning agents-contain animal protein that is able to enter the hair shaft. This provides a temporary strengthening of hair shafts that have been damaged or "weathered". Conditioners are further identified as (1) "instant" that are applied immediately after shampooing and then rinsed out, (2) "deep conditioning" that are left in the hair for up to 30 minutes after shampooing to enhance hair-shaft repair-protein conditioning agents are often ingredients in "deep" conditioners, and (3) "leave-in" conditioners that are left in the hair until the next shampoo. Leave-in conditioners may be especially useful for kinky hair to aid in hair styling.

  • Hair Styling Agents

    Hair styling agents are used to create the styling "look" preferred by the individual. Leave-in conditioners (pomades or glycerin-based products) are common styling agents for kinky hair. A common styling aid for straight hair is products that increase the appearance of volume (body, fullness and shape). Many products are available in this category of styling agents (see Hair Volume).

    All of the styling agents contain polymers to enhance the sheen of hair and the "hold" of the style through everyday events. The polymers are (1) alcohol-based, (2) wax-based, and (3) water-based, each with properties that may make the product optimal for the individual (see Hair Styling Products).

    Permanent Waving

    Permanent waving uses complex chemical interactions between styling chemicals and hair to alter the structure of hair and render it pliable for converting straight hair into wavy or curly hair. The procedure is performed more quickly and efficiently by a licensed beautician or cosmetologist in a salon. Failure to perform the procedure carefully-for example, to neutralize the chemicals that alter hair structure-can result in cumulative damage to hair.


    Hair straightening is accomplished by three types of procedures:
  • Mechanical, which uses heavy pomades to hold the hair in a minimally kinked form. While this method causes least hair damage, it is also the least effective in straightening hair;

  • Heat, which uses hot-combing and hair "ironing" to alter the chemical structure of hair so it can be combed out straight. The application of high heat and hard combing can cause hair loss in some individuals; and,

  • Chemical, which uses alkaline chemicals to alter the structure of hair-shaft proteins (keratins) and render the hair easier to be molded into a straighter form. The most potent chemical hair straightener is a lye solution, which is also dangerous to use and is little used today. Ammonium bisulfite creams are milder than lye solutions, but also less effective. Overall, chemical hair straightening is most likely to cause permanent damage to hair.

  • Coloring Agents

    Four types of hair coloring agents are available for use by the consumer:

  • Gradual, a type commonly used by men who want to inconspicuously change gray hair back to its original color. The coloring agent is an aqueous solution of a metal salt such as lead acetate. The colored hair may be rendered dry and brittle.

  • Temporary hair colors are added after one shampoo and removed with the next. The coloring agents are actually dyes adapted from the textile industry.

  • Semi-permanent are also adapted textile dyes, polymers or vegetable dyes that will stay in the hair through multiple shampoos.

  • Permanent coloring agents do not require re-dyeing until the colored hair grows out and "shows roots". While these are the most popular of all hair coloring agents, they are also the most damaging to hair. The dye is permanent because it chemically alters and binds to the hair cortex proteins (keratins); this alteration of keratins decreases the strength of their chemical bonds and this decreases the strength of the hair shaft.